When most people think about the Border Collie, we predict that they think the following:

• Wicked smart dog
• Strong work ethic
• Crouching herding style with plenty of “eye”

And they are right, of course.

There isn’t much a Border Collie can’t do, and few animals it can’t manage. The Border is versatile on a farm and ranch, of course, but organizations like K9 Conservationists and Conservation Dogs Collective confirm that Border Collies are among the breeds used for tasks like detecting invasive species, monitoring rare wildlife, and searching for animal scat or evidence in conservation projects. Borders have been trained as service dogs, therapy dogs, and in Italy, a Border Collie named, “Zen” teaches other dogs how to rescue people in Italy’s avalanche-prone Dolomites. There are several “avy” dogs, actually, including “Ripp” in Colorado. A trained Border Collie can cover search areas that would take 50 people an entire day to search in just 30 minutes, making them invaluable in time-critical rescue situations where victims typically have only a 30-minute survival window. Just saying.

Yes, Border Collies pretty much do it all, which is why this post is not about the breed’s versatility.  It’s about something most of us don’t think of at all when we think about the breed. Its coat.

In defense of those of for whom coat isn’t at the forefront of thought, the Border Collie is most respected as a working dog, so something like its “outwear” is an afterthought.

But did you know that the breed actually comes in two coat varieties, the rough and the smooth? In the collage seen below, you can easily spot which is which (hint: It is not the cow, goose, sheep or goat):

The rough variety has a medium length coat with feathering on his or her chest, belly, and legs. S/he might also have a dense, wooly undercoat together with long guard hairs. The smooth, meanwhile, has a coarser feeling coat that is short all over with minimal to no feathering. And some dogs have a little of both.

For anyone wondering, breed standards address this. The FCI standard reads, “COAT Hair: Two varieties: Moderately long or Smooth. In both, topcoat dense and medium textured, undercoat soft and dense giving good weather resistance. In the moderately long-coated variety, abundant coat forms mane, breeching and brush. On face, ears, forelegs (except for feather), hind legs from hock to ground, hair should be short and smooth.

The AKC standards reads, in part, “Coat: Two varieties are permissible, both having close-fitting, dense, weather resistant double coats with the top coat either straight or slightly wavy and coarser in texture than the undercoat which is soft, short and dense. The rough variety coat may vary in length without being excessive. Proper texture is more important than length…”

When it comes to the genetics of rough-coated versus smooth-coated Border Collies, the easy answer is that it mainly involves a gene that controls the coat texture, but the actual answer, while fascinating, is more complex.

Coat length is controlled by a single gene called FGF5 (or the L locus), and its two versions (called alleles) work like competing instructions for how long the coat should grow. We learned after a bit more reading that a rough coat is recessive to a smooth coat. This means that if a pup inherits the smooth coat gene from one parent and any gene from the other parent, it will have a smooth coat. The rough coat trait is caused by specific mutations in the FGF5 (Fibroblast Growth Factor 5) gene. This gene normally tells hair to stop growing at a certain length by signaling the transition from the growth phase (anagen) to the regression phase (catagen) of the hair cycle. When the gene is mutated, it can’t properly control hair growth, which results in longer, rougher coats.

Scientists have identified several different FGF5 mutations that all cause the same rough coat effect in different dog breeds, including Border Collies. Genetic testing can now tell us what coat type genes a dog carries, even if they appear smooth on the outside.

We’re not sure at this point if owners of different Border Collie “lines” (something we’ll cover in a different post) have done genetic testing to prove an observation passed along anecdotally, and that is that the Northumbrian and Wiston Cap “types” are most apt to have a rough coat, while the Nap type is characteristically smooth-coated. We’re working on this. As they say, watch this space.

Images in collage: Border Collie with smooth coat by Eudyptula/iStock; rough coated Border Collie by Tepepa79/iStock. Goose by Christian Bowen, Goat by Nandhu Kumar, sheep by jsb-co, and cow by Jean Carlo, all from Unsplash